One Function Absent When Playing Timeline To TV.

Question

This is not so much a serious problem as a minor curiosity.
I use a Datavideo DAC 100 A/D Converter to play my timeline on a TV.
It functions beautifully. However, yesterday I noticed a slight peculiarity.
I was using the Left and Right Arrow keys which enable you to either move the picture by one frame, or (if held down) play the movie slowly.
Whilst I could jump the video one frame at a time on the TV, I could not get the video to play slowly.
Strangely enough, the picture on my eMac monitor was moving slowly (as usual) but the picture on the TV was static.
On close examination, I discovered that when I pressed the arrow key, the image on the TV moved one frame and froze. Then, a few seconds later, when I released the key, the image jumped to the point that the cursor had reached on the timeline. Whilst all this was occurring, the video in the monitor was moving normally (slowly) along.
Not a real problem but can anyone explain why the TV image does not move exactly like the monitor's in this instance?
As far as I can tell every other function plays normally on the TV.
Ian

Answer 1

Hi Ian,
From my experience while debugging filters, I learned that FCE internally keeps two different display buffers for the canvas and for the firewire connection, only when the latter is present (they are like two parallel output channels with different parameters: for example the firewire one has a field by field processing while the canvas one has a frame by frame processing, etc...). This is quite understandable, since the output types are very different.
So the CPU may be overloaded while controlling both such output channels, and it seems FCE gives priority to the canvas over the firewire, even if this does not make much sense to me (I'd do the opposite...).
I avoid the effect you are describing in your post, by making sure audio is mixed down and the canvas window zoom is NOT 100% (Fit to window is usually the best bet): 100% forces FCE to handle both fields in each frame ALSO in the canvas. And this seems too much for my CPU ...
I hope this explains your case.
Merry Christmas!
Piero
PS: About iMovie: the output format in iMovie is the same (DV stream) for both firewire and .dv file outputs. It's just a guess, but probably this requires less CPU power to handle both output together...